1. Field of the Invention
The present invention relates to a method of processing output data from a geomagnetic sensor.
2. Background of the Invention
Active R&D efforts are being conducted today on vehicle-mount navigational apparatus which directs a vehicle to its destination by reading map information from a memory and displaying it on a display device together with the present location of the vehicle. One of the indispensable components of this navigational apparatus is a direction sensor for detecting the direction of the vehicle. The direction sensors proposed thus far are geomagnetic sensor which detect the position of the vehicle based on geomagnetism (i.e., the earth's magnetic field). One of the major problems of this geomagnetic sensor is its high susceptibility to disturbances from external magnetic fields. When the vehicle passes a railroad crossing or an iron bridge or when a larger car (e.g. a truck or bus) passes by the vehicle, the sensor will produce an output containing a significant error.